textproduct: Albany

WHAT HAS CHANGED

Winter Weather Advisory expanded to include southern Herkimer County for up to 3-5" of snow, and to the southern Greens for up to 4-7" where there will be some upslope enhancement to snowfall totals. Also, new advisory was issued late this afternoon through early tomorrow morning for the eastern Catskills, Mid Hudson Valley, Taconics, and southwestern New England for a glaze up to a few hundredths of an inch of freezing rain. Also added in slight chance PoPs Friday night into Saturday AM with a compact upper low potentially dropping south over the forecast area.

KEY MESSAGES

1) Light to moderate snowfall amounts (mainly near and north of I- 90) along with light ice accumulations (mainly south of I-90) will lead to slippery travel conditons this afternoon into Wednesday.

2) We continue to monitor the potential for a coastal storm system to impact eastern New York and western New England late this weekend/early next week, but confidence remains very low for this portion of the forecast.

DISCUSSION

KEY MESSAGE 1... As of 1:50 AM EST...GOES 16 Nighttime microphysics satellite imagery shows mid and high clouds streaming over the area early this morning ahead of a clipper system that will bring widespread light to moderate precipitation to the region today. Despite light winds and widespread snowpack, these clouds are keeping temperatures much warmer than the past several nights, with temperatures ranging from the upper 10s in the Mid Hudson Valley and western CT to around 0 in the upper Hudson Valley.

This morning starts off dry and chilly (albeit warmer than the last several mornings), but an upper low and associated sfc cyclone will track north of the Great Lakes will approach from the west today. As the system's warm front lifts north across the region, we are expecting a band of snow to track from west to east along and north of I-90 late this morning (west of I-87) and early this afternoon (east of I-87). Precipitation should be fairly widespread across our northern zones this afternoon as a secondary sfc low develops near Lake Ontario along the warm front.

With strong low to mid-level warm advection and isentropic lift, a band of mid-level FGEN, and CVA associated with the ULL, forcing looks fairly strong with this system, and there will be increasing moisture ahead of it thanks to a strengthening 850 mb southwesterly LLJ. With this lift intersecting the DGZ this afternoon and early evening, there is a roughly 30-40% chance for snowfall rates to reach 1" per hour across the southern ADKs, upper Hudson Valley, and southern VT. The best chance is in the southern ADKs, where low-level southerly flow will lead to upslope enhancement. For areas along and north of I-90, this evening's commute could be slippery and snowy.

By 00z, precipitation begins to spread southeastwards to areas south of I-90. With the strong mid-level warm advection resulting in a warm nose aloft, latest guidance is suggesting mixed precip, including freezing rain, across portions of the eastern Catskills through the Mid Hudson Valley into southwestern New England. This will result in slick travel conditions, especially considering how cold the antecedent airmass has been. However, precipitation here generally looks to fall mostly after the end of the PM commute. As the best lift and moisture moves off to our east this evening (03-06z), model forecast soundings show a mid-level dry slot punching in from the west, which will result in a loss of cloud ice. Sfc temps remain below freezing, so this will result in some patchy freezing drizzle across eastern NY and western New England.

Precipitation looks to come to and end for much of the region by 12z Wednesday as the system's cold front tracks through the region. However, the upper trough will be overhead to start the day Wednesday and slide eastwards into New England during the day. Moist cyclonic flow and low-level NW winds will lead to continued upslope snow showers across the western ADKs and southern Greens Wednesday into Thursday. There may be some enhancement Wednesday afternoon associated with an inverted trough from a strengthening sfc low off to our east, and there will be some lake enhancement across the southern ADKs.

Given the above, there were several headline changes made with this forecast package. First, southern Herkimer and northern Fulton County were added to the existing winter weather advisory, mainly due to the snow expected with the clipper this afternoon and evening (3-5" for these areas). The southern Greens were also added, with higher amounts here (up to 4-7") with a combination of synoptic snow from the clipper this afternoon and persistent upslope through Thursday AM. Finally, a new advisory was issued from 3 PM today through 6 AM Wednesday for the eastern Catskills, Mid Hudson Valley, Taconics, and western CT/MA due to the potential for a glaze to a few hundredths of an inch of ice accumulation with the freezing rain/freezing drizzle this evening and tonight.

The upslope snow showers should diminish in coverage and intensity Thursday, ending by the afternoon or early evening as winds weaken, turn more to the north, and the ULL tracks further to the east of our region. Will also mention that a deepening coastal low to our east Wednesday and Thursday will result in a tightening pressure gradient with high pressure building over the center of the country, so Wednesday and Thursday both look breezy, especially in the typical NW flow channeled areas where some gusts to 25-30 kt are expected.

KEY MESSAGE 2... Tranquil weather is expected Thursday night and Friday with high pressure building over the region, but 18 and 00z guidance is suggesting that a compact ULL/TPV will drop south into upstate NY or northern New England Friday night into Saturday morning. There remains considerable uncertainty in the track of this small system, but with most guidance now suggesting at least some impact, we collaborated with neighboring offices to add some slight chance PoPs, mainly across northern and high- terrain areas, Friday night into Saturday.

Saturday afternoon through at least Sunday morning looks to feature high pressure building back overhead and tranquil weather, but we will then have to watch a potential coastal storm late Sunday or Monday. The synoptic setup looks to feature a deamplifying southern stream shortwave tracking south of our region, and it may or may not phase with a northern stream shortwave. Given the potential complex interaction (or lack thereof) between these features, forecast confidence is quite low, and will likely remain low for at least a few more days. A wide range of potential forecast outcomes remain on the table, with a complete miss out to sea possible, as it a storm track close enough to the coast that any snow mixes with or changes to rain for portions of eastern NY/western New England. Will continue to monitor this time period closely over the next several days.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Through 12z Wednesday...VFR conditions will likely prevail through the first 7 hours of the TAF period. Then light snow will develop along a warm front advancing eastward across the region this afternoon. Best likelihood for a few hour period of steady -SN with IFR conditions is at KALB/KGFL/KPSF, with lower chances at KPOU so will mention a PROB30 there. -SN will become spotty at KALB/KPSF by early evening, then a period of steadier snow will re-develop along the system's cold front after 00z with prevailing IFR conditions expected. There will be warm layer aloft at KPOU, where a wintry mix of -PL/FZRA is mentioned. The steady precip then ends between 02z-04z, however with lingering low level moisture and drying aloft, will mention PROB30 for patchy FZDZ through 06z Wednesday. Winds will initially be light and variable, becoming southerly around 5-11 kt this afternoon with occasional gusts near 20 kt at KALB.

Outlook...

Wednesday Night: Low Operational Impact. Breezy. NO SIG WX. Thursday: Low Operational Impact. Breezy. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: Low Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Low Operational Impact. Slight Chance of SN.

ALY WATCHES/WARNINGS/ADVISORIES

CT...Winter Weather Advisory from 3 PM this afternoon to 6 AM EST Wednesday for CTZ001-013. NY...Winter Weather Advisory from 3 PM this afternoon to 6 AM EST Wednesday for NYZ047-051-058>061-063>066. Winter Weather Advisory from 10 AM this morning to 1 AM EST Thursday for NYZ032-033-038-082. MA...Winter Weather Advisory from 3 PM this afternoon to 6 AM EST Wednesday for MAZ001-025. VT...Winter Weather Advisory from 10 AM this morning to 1 AM EST Thursday for VTZ013-014.